As the degree of integration of electronic parts increases when they are mounted, a problem frequently occurs in that the reliability of the product falls or the life of each electronic device is shortened due to heat occurring from each electronic device mounted on a board. In particular, such deterioration is more noticeable in the case of a diode operating by a reverse bias such as a Zener diode or a light-emitting diode or a power diode that can handle a volume of current.
FIG. 1 is a drawing explaining a traditional diode package. As illustrated in FIG. 1, the traditional diode package is formed by welding both opposite sides of diode chip 10 to the ends of the lead wires 30 and 40, and by packaging the diode chip 10 and the lead wires 30 and 40 together with a molding compound 20. Reference numbers 30a and 40a denote welding points.
At this time, it is necessary that the two lead wires 30 and 40 are aligned and welded so that they are arranged in line. However, it is a very cumbersome task to perform the welding process in the state that they are aligned to be arranged in line and to package them with the molding compound 20 in the state that the lead wires 30 and 40 are welded and then they keep their shape.
Furthermore, since the lead wires 30 and 40 are formed with a thin wire, its heat radiation efficiency is not good. While the lead wires 30 and 40 should be thick in order to increase the heat radiation efficiency, the diode chip 10 should be enlarged in size since the lead wire welding portion 30a and 30b should be very thick. Accordingly, it is difficult to increase the heat radiation efficiency when the diode chip 10 is small in size.
As described above, in the traditional diode package, it is very cumbersome to manufacture it and there is limitation in increasing its heat radiation efficiency.